Razor blade stropper



Jan. 10, 1933.

A. D. BOULANGER ET AL RAZOR BLADE .STROPPER Filed July 19, 1928 2 Sheets-Sheet 1 g 3 N VB?! TORS Jan. 10, 1933. A, D, B U LANGE T- 1,893,642

RAZOR BLADE STROPPER Filed July 19, 1928 2 Sheets-Sheet 2 I INV 101m. (2 Q WM M Patented. Jan. 10, 1933 UNITED STATES PATENT OFFICE ANTHONY D. BOULA GEE. Ann FRANK r. HUBRIGH, OE RincE iEnn PARK, NEW

JEEsEY, ASSIGNORS E ONE-THIRD T0 FRANK n. BOUL'ANGER (2D), or a neEEIEL-E- PARK, NEW JERSEY RAZOR BLADE sTRoPrEa Application filed July 19,

This invention is concerned with a device for stropping safety razor blades and may or may not be incorporated in a razor.

The principal object of the invention is to increase the sensitivity of the mechanism which swings the blade upon reversal of the direction of stropping, so that the possibility of cuttin the strop may be practically eliminated. It is an object also to embody in a stropping device attaining the principal object as stated above, certain features of design which make the device compact; comparatively inexpensive to manufacture, beneficial to the strop and capable of use as a stropping device alone or as a part of a safety razor of the so-called auto-strop type.

A preferred embodiment of the invention is described hereinafter and is illustrated in the accompanying drawings.

In the drawings: Fig. 1 is a side view of a safety razor embodying the present invention;

Figs. 2 and 3 are vertical sectional views taken in opposite directions on the lines 2-2 F and 33 respectively of Figure 4 and showing the position of the parts as the blade is moved along the strop;

Figure 4 is a top plan view of the same razor;

Figure 5 is a perspective view of the nonrotating strop engaging rod;

Figure 6 is a perspective view of the blade carrier frame reniovedfrom the razor;

Figure 7 is a perspective view from above of the razor during stropping;

Figure 8 is a perspective view from below of the razor with the parts in position for shaving;

Figure 9 is a front view partly in section;

Figure 10 is a perspective view of the base frame of the razor;

Figure 11 is a perspective view of the movable blade guard.

The razor disclosed here has a handle 1 threaded into a hole 28 in a downwardly extending U shaped portion of the base or supporting frame 2. Pivotally mounted to rock with respect to the base 2istheblade carrying part of the razor. This blade carrier is a frame having arms 3 turned downtionof the base (Fig. 9).

1928 Serial No. 293,984.

, The arms a extend upwardly from the main body of the frame and receive between them the strop engaging rod 5 and the blade holder 6. The rod 5 has rectangular lugs 19 which fit inthe holes 19 provided in the arms 4 and is therefore non-rotatable. Theblade holder 6, as shown, consists of a piece of sheet metal bent around a pin so as to be rigid therewith. The pin rotates in holes in the arms 4 and has fixed to it a small pinion 7 at one end on the outside of the arm. I

The main part 8 of the carrier frame is bent upwardly and, at its edges, outwardly to form guide lips for the strop. The edges are preferably slightly above the level of the lower side of the rod 5 and in any event are substantially at that level so that when the strop,

passes over both edges and under the rod, it is slightly snubbed and relative movement between it and the carrier is resisted. V

The base or supporting frame 2 has an upright side member which forms the gear sector 9, being toothed on its upper edge. This edge is curved on a radius from the pivotal axis of the blade carrier at 16. Thus the pinion 7 engages the gear sector or rack 9 inall positions to which the carrier is rocked. Because of such engagement the rocking movement of the carrier is transmitted to the blade holder causing the latter with blade 10 to swing about from one strop engaging position to another. p p a A blade guard 11 is provided andis of a general type well known but somewhat modified here to fit the base which differs from the ones in common use in several respects. The

guard 11 has a rearwardly extending portion.

12 to be engaged by the users thumb or finger in moving the guard about its pivot pins 13 on the base frame 2. The forwardly extending portion has the usual prongs 14 on which the cutting edgeof the blade rests and-the backwardly bent members 15 for engaging the corners of the blade when the guard is swung upward tomeet it.

Suflicient friction to prevent movement of the guard, except when desired by the user,

is afforded by the engagement of pivot lugs 24 with the ofi-sets 25, 26 on the base 2; by the engagement of the pins 13 with the Walls of the openings 29 in lugs 2e and, in a greater amount, by the bearing of the curved lugs 22 upon the similarly curved portions 21 of the base. It will be noted that the pivot lugs 24 are near the center of the razor and that the bracing lugs 22 are near the sides. This arrangement gives stability and is very satisfactory. Further, it adds to the ease of man ufacture since lugs 24 are turned down from an offset portion of the guard, leaving lugs 22.

The manner in which the stropping is done will be apparent. A strop 18 is guided between the curved member 8 and the rod 5.

'With one end of the strop secured and the other held by the user, the razor is moved back and forth on the strop, the strop engaging members 5 and 8 serving as guides during the strokes.

At the end of each stroke, upon reversal of the direction of movement of the handle 1, the blade carrier is rocked. Since the effort required for this is extremely slight, the rocking occurs without slip between the strop and the carrier frame and the blade is removed bodily from the strop. Simultaneous with the rocking, because of the direct geared relation between the carrier and the blade holder, is the swinging of the blade from a strop engaging position on one side of the razor to a similar position on the other side. The extent of rocking movement of the carrier frame is determined by the strop. During all of the stroke, the frictional drag of the members 5 and 8 on the strop tends to rock the carrier further and hence to press the bladeagainst the strop, thus giving the proper condition for stropping.

The problem with which the present invention is concerned arises at the end of the stroke where it is necessary to swing the blade to the opposite sideof the razor for the return stroke. If the cutting edge of the blade is not moved away from the strop instantaneously upon reversal of the direction of movement of the razor, the strop either will be cut through or will be nicked, thus being made either wholly useless or less effective. It will be appreciated that the blade reversing mechanism must be extremely sensitive in order to respond to the very first movement of the razor in the reverse direction.

Heretofore the constructions found to be most satisfactory have included a roller engaging the strop and geared in'some manner to the pivot rod of the blade holder. Some devices have had in addition rocking blade carrier in order to swing the blade bodily away from the strop. The rotation ofthe blade holder in these devices has nevertheless been caused by a roller and therefore has not.

The present invention is based upon the use of a rocking blade carrier in conjunction with a means to make the rotation of the blade holder about its axis dependent upon and coincident with the rocking of the blade carrier. The rocking is caused by the frictional resistance between the strop and the strop engaging members, which are part of the carrier. As a refinement, the carrier has a relatively long radius and the strop engaging members are at such a distance from the axis of the carrier that a good leverage is obtained. Thus a very slight effort is required to rock the carrier, with the result that the chance of slip between the strop and the'strop engaging parts of the carrier during reversal of the blade position well may be said to be negligible; The increased sensitivity of this device in contrast to known devices is marked and is of such a degree as to make it practically impossible to cut the strop even when the strop is allowed to sag.

It is worthy of notice that one of the chief causes of the decreased sensitivity of the roller type of blade swinging mechanism after a period of use is not present in this construction shown here. The roller, of course, in the common types of stropper does not act as such during the greater part of the stroke but only during reversal. Between reversals, the roller slides on the strop. In time a slight flat is produced and While it is not of such extent as to vary appreciably the spacing between the strop engaging members, it does increase materially the resist- 1 ance to rotation of the roller. Hence the chance of a slight slip between the strop and the roller is increased and with it the danger of nicking and cutting the strop. In the present construction, the chance of slip, even though the rod 5 becomes flatted, is at a minimum. since the effort required to rock the carrier is not sufiicient to overcome even the decreased frictional resistance.

In our Patent No. 1,845,956, dated February 16, 1932, we disclose the advantages of aluminum or a like metal, as a material for a roller used as a strop engaging member. lVe find that pure or substantially pure aluminum, is an excellent material for the rod 5 of the present device. WVe regard this as an important feature of the invention since, in addition to metallizing the strop, as described in our application mentioned above, the rod of aluminum or the like adds to the sensitivity of the device in that it in creases the friction between the strop and the carrier. With such a rod, it is not necessary to treat the strop which sticky oils which improve the frictional qualities only at the expense of the stropping qualities.

It willbe understood that the novel features relating to the blade reversal may be used in a stropping device not a part of a razor as well as in the manner disclosed.

Other departures from the specific device described in this application are possible. The size and shape of the parts may be varied to suit different types of blade. Various sorts of blade holder and blade guard may be used as may be desired. The details of the blade reversing mechanism, the particular field of the present invention, are likewise subject to variation within the scope of the following claims.

I claim:

1. A stropping device comprising a base, a blade carrier mounted to rock with respect to said base, a blade holder pivotally mounted on said carrier and means transmitting the rocking motion of said carrier to said holder to swing the latter about its pivotal axis, said carrier comprising, as strop engaging members, a transverse non-rotatable circular rod and a plate parallel thereto and spaced therefrom, said plate having transverse edges at a higher level than the under surfaces of said rod.

2. In a razor, a base comprising an upright side member forming a gear sector and a central downwardly extending portion, a frame pivotally mounted in the downwardly extending portion to swing in a direction parallel to said side member, a movable blade guard on said base above the pivotal axis of said frame, spaced strop engaging members on said frame at a level above said guard, a blade holder pivotally mounted to swing about the upper edge of said frame and a pinion engaging said gear sector and adapted to swing said blade holder.

In testimony whereof we have signed our names to this specification.

ANTHONY D. BOULANGER. FRANK P. HUBRICH. 

